Drafting and plotting instrument.



H. HOWARD.

DNAPTING AND PLOTTING INSTRUMENT.

APPLICATION FILED DEO.12,1913.

rTED STATES PATENT FFICIS."

HENRY HOWARD, OF BROOKEVILLE, MARYLAND.

DRAFTING AND PLOTTING INSTRUMENT.

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To all whom it may concern Be it known that I, HENRY HOWARD, a citizen vof the United States, residing at Brookeville, in the county of Montgomery and State of Maryland, have invented certain new and `useful Improvements in Drafting and Plotting Instruments; and I hereby declare `that the following4 is a full, clear, and exact description thereof, reference being had to the accompanying drawings,

which form part of this specification.

This invention'is a novel improvement in drafting and plotting instruments and its object is to provide a very convenient tool whereby figures of any desired outline can be accurately and quickly plotted, and which can be used as a drafting tool in place of a 'lsquare and angle, and can be also used as a Section lining tool; and whereby by alternately fastening the two end members to the board or surface on which it is being used the tool can be shifted anywhere over a large area of surface, and an exact relation between the end members of the instrument will be maintained. j

The implement in brief comprises a protractor, a triangle and an L-square; and parallel links connecting the straight edge of the protractor with one leg of the triangle and forming therewith a parallelogram; and parallel links connecting the other leg of the triangle with one leg of the L-square and forming therewith another paral1elogram, so that if the protractor be attached lto a board the L-square will always be held at any predetermined angle to a given perpendicular' or horizontal line in any positionA to which it can be moved, as permitted by the intermediate connections; or if the L- square be fastened to the board the protractor will be held at the same relative angle thereto and in whatever position it can be shifted as permitted by the intermediate connections. When used on large surfaces after the protractor or L-square is adjusted to the desired angle, and one of these inembers fastened, such angle will be constantly maintained by the other member and the instrument can be shifted along the surface from top to bottom, or from end to end, by fastening the lL-square to the board before the protractor is loosened (or vice versa) and then loosening'the latter and bringing itl up to the square (or vice versa) and fasteninfr it before releasing the T-square.

A tfurther object of the invention is to so Specification of Letters Patent. Patented Man 10, 1914.

Application led December 12, 1913.

Serial No. 806,299.

construct the parts that there will be a minimum of wear at the joints or pivots of the` I further provide means whereby the implemcnt may be used for cross sectioning in a simple and accurate manner to insure uniformly spaced parallel section lines.

I will explain the invention with reference to the accompanying drawings in which- Figure 1 represents a view of the complete implement. Fig. 2 is an enlarged section through one of the joints, on line 2-2, Fig. 1. F ig. 3 is a detail section through the compensating device, on line 3 3, Fig. 1.

The preti-actor 1 may bc of ordinary form and construction having a straight edge and a scale as usual; the triangle 2 may also be of ordinary construction; and so may the L-square 3. The straight bar 1u of the protractor is connected to one of the sides of the One leg of the L-square 3 is similarly con-r nected by parallel links 5 to the leg of the triangle at right angles to that leg to which the links 4 are attached. The links 5 are connected to the leg of the L-square 3 by means of tubular rivets 5a so that thumb tacks can be inserted therethrough, and the links 5 are also preferably connected to the triangle 2 by hollow rivets 5b. The endsof the links 1l and 5 at the apex of the triangle are connected by the same rivet 5. It will be seen that practically all the links are in the same plane, and this is an important practical feature of the construction of the device. The links being of the saine length it follows that the leg 3 of the L-square will always stand parallel with the straight edge 1 of the preti-actor no matter in what positions these parts may be adjusted; conseuently the angle with respect to a given line at which the leg 3 of the L-square is to be used can be readily determined by correspondingly shifting the protractor with respect to such line. Any desired angle can be readily calculated on the protractor llO by means of the scale thereon, which can be read in the usual manner, and the straight edge of this protractor has a notch ln which is disposed atthe axis of the protractor and by sticking a pin in said notch or making a mark with a pencil in saidvnotch and at the proper point on the curved edge 1f of this protractor and drawing a line on the surface between said points, the angle at which the L-square is set relative to any given. perpendicular can be determined and maintained by adjusting the edge 1e of the protractor to said line` Similarly the arm Beef the square can be placed on any given line as a base or perpendicular or as a line of latitude or longitude and the protractor secured rigidly in place on the board by inserting thumb tacks through the tubular rivets, and such arm of the L-square will then always maintain the same true parallel relation to the said'line, no matter to what point .on the surface it may be moved.

To compensate for any lost motion or possible wear on the rivets I provide each parallelogram withv an automatic take-up device, which comprises a sectional link 6 arranged between the protractor and angle, anda similar link 7 arranged between the angle and L-square. Thetlinks 6 and 7 are each composed of two sections, one of said sections has a screw socket 6b on its meeting end beside an eye 6c on the meeting end of the opposite section; through this eye passes a screw 6d that is tapped into the socket, and av helical expansion spring 6i is interposed between the eye and the head of the\- screw, thus making an adjustable springten\sioned link, which automatically takes upany looseness or wearA of the pivots, and keeps the protractor and angle held uniformly distanced by the links a and keeps the L- square and triangle held uniformly dis- `tanced by the links 5. The take-up links 6 and 7 are preferably connected to the protractor triangle and square by tubular pivots, andare arranged in a median line between .the parallel links.

When using the implement as a section liner, a bar8 is employed, said bar having perforations 8al in its ends for lthe passage of thumb tacks, and having its side edges serrated, and after the L-square has been set to the desired angle of the section lines, and the protractor fastened to the surface; said bar 8D is secured beside the IL-square, as

' shown in Fig. l, adjacent the part to be tid section lined, in such position that a serrated edge of this bar can vbe contacted by the apex or point of one of the ends of the L-square. rlhis bar 8 vis provided with equally spaced serrationls on its sides, the serrations on its opposite sides being of dierent depth or Width, and by successively u engaging the L-s nare with Vthe /notches in the side of said ar the lL-square can be used for section lining in the mana ner vknown to draftsmen; and the section lines will be uniformly spaced apart according to the distance apart of the adjacent notches in the bars 8. v

rlhe invention practically `provides three instruments in one. Angles can be marked off by the protractor without any adjustment; and deiiections right and left can be taken direct from the protractor without any adjustment. When theprotractor is to be used the lL-square should be fastened, and

when the ll.square is to be used the protractor should be fastened; and they can be used alternately .on the same surface and their predetermined relation to any given horizontal or perpendicular maintained'by simply fastening one before releasing the other; and when thus used they never lose the desired angular relation no matter to what positions on the surface they may be shift-ed. rlFhe instrument can be readily used as a section liner by attaching bar 8,

or its equivalent, to the surface to be sec-l n tion lined, and using the implement in connection therewith-as above described;

I preferably use the la-square and the ends of this square are beveled as indicatedv at 3 at an angle qf 45 to its sides, and also at right angles to the hypotenuse 2n of -the triangle 2 so that any time it is desired to draw a line at right angles to said hypotenuse, or to the hypotenuse of the triangle formed by the legs of the L-square, such line can be obtained by drawing a line along the hypotenuse of the triangle and a line across the points of the l.sqi1are while the parts are held stationary The hypotenuse 2 of the triangle 2 always stands at an angle of to a line drawn between the points or hypotenuse'n of the L-square. This angle of 90 between the hypotenuse of the triantermediatel member and a square, parallel v links connecting the vprotractor and intermediate member, and parallel links connecting the square and intermediate member, the

pivots connecting said links to the square,

and to the protractor being tubular for the insertion of devices for attaching the same toa surface.

2. rlihe combination of a` protractor, a square and an intermediate member, parallel `links Vpivotally connectin the protractcrl with the intermediate mem er, parallel linke pivotally connecting said intermediate inember to the square, and devices connecting the protractor and member and the member and square to compensate for lost motion and wear on the pivots.

3. The combination of .a protractor, a -square and an intermediate member, parallel links pivotally connecting the protractor with the intermediate member, and parallel links pivotally connecting said intermediate member to the square, and a compensating link connected to the protractor and intermediate member between their parallel connecting links, and a similar compensatingv link connecting the triangle and square between their parallel connecting links.

4;. The combination of a protractor, a square and an intermediate member, parallel links pivot-ally connecting the protractor with the intermediate member and parallel links pivot-ally connecting said intermediate member to the square@ and intermediate spring links between the parallel links for compensating for wear on the pivots, said parallel links being attached to the protractor. and to the triangle by tubular rivets, for the engagement of fastening devices.

5. l1he combination of a protractor, a square, and an intermediate member, parallel links pivotally connecting the protractor with the intermediate member, and parallel links pivotally connecting said intermediate member to the square, said connecting links being attached to the protractor and to the triangle oytubular rivets; with a compenand intermediate member between the eating device connected to the protractor arallel links, and a similar compensatin device connected to the intermediate mem er and square between their connecting parallel links, substantially as described.

6. In an implement of the character specitied, the combination of a protractor, a triangle and an L-square, parallel links connecting the protractor and triangle, and parallel links connecting the triangle and L- square, the pivots connecting said links to the L-square and to the protractor being tubular for the insertion of fastening devices for attaching the same to the surface. 7. The combination of a protractor, an L- square and an intermediate triangle, parallel links pivotally connecting the protractor with the triangle, and parallel links pivotally connecting said triangle to the L-square, a sectional spring link connected to the protractor and triangle intermediate the parallel links, and a similar link connected to the triangle and L-square intermediate their parallel connecting links, substantially as and for the purpose described.

In testimony that I claim the foregoing as my own, I affix my signature 1n presence of two witnesses.

HENRY HOWARD. Witnesses:

ARTHUR E. DOWELL, LILLIAN E.' WrrHAM. 

